Why military activity in the Black Sea may be driving dolphins to the brink: ScienceAlert

Along with the thousands of men, women and children who have died since Russia invaded Ukraine in February, there have been hundreds of casualties in the Black Sea among its resident dolphin and seal populations.

Scientists studying the area have reported an “unusual increase” in strandings and bycatch – when the animals are inadvertently caught by fishermen – of dolphins, seals and whales in the spring and summer of 2022, according to a recent report by ACCOBAMS, or Symphonia for the conservation of cetaceans of the Black Sea, the Mediterranean Sea and the contiguous Atlantic area.

“Russia’s war against Ukraine escalated in February 2022 puts the entire Black Sea basin under enormous threat. Military activities in the sea and coastal areas may affect marine life in the area, including cetaceans,” the report said.

More than 700 deaths, mostly of dolphins and porpoises, have been recorded off the coasts of countries bordering the sea, including Bulgaria, Romania, Turkey and Ukraine, according to Erich Hoyt, a researcher at Whale and Dolphin Conservation who advised the ACCOBAMS scientists.

Investigators are working to determine the cause of the deaths that have been observed, but the ongoing war – and the potential threat posed by drifting mines – are making data collection and boat surveys difficult.

There have been reports of dolphins washing ashore with physical injuries, such as burns, which could be a direct result of being caught in the crossfire. Ivan Rusev, director of research at Ukraine’s Tuzla Estuaries National Nature Park, said earlier this year dolphins washed up with burn marks from bombs or mines, while others appeared unable to navigate or as if they hadn’t eaten in days.

But the increase in strandings and dolphin bycatch could be a direct consequence of the loud noises associated with the war.

“Dolphins and porpoises rely on sound to navigate, find food and communicate with each other,” Hoyt told Insider.

“Noise from increased vessel traffic may have some impact, but the sounds of surface or underwater explosions may disorient, injure or kill dolphins and porpoises within a few miles, or cause increased strandings or bystanders. catches”.

Dolphins, porpoises and whales have an acute sense of hearing and use echolocation to map their environment.

They emit short, pulsating “clicks,” similar to a finger snap, that travel through the water until they encounter an object and bounce back to the dolphin.

But the dolphin’s unusual ability to interpret the sound that returns to identify food and understand their environment can be disrupted by loud noises.

Dolphins also use sound, similar to a whistle, to communicate with each other, and have even been documented using verbal labels to address each other—in a word: names.

Sound also travels much farther and about four and a half times faster through water than through air, making the impact of explosions at sea even more devastating.

Although scientists are working to confirm the reasons for the increased deaths, Hoyt said the noise breaks could disorient the dolphins, leading to an increase in them stranding on shore or being caught in a fisherman’s net.

Another factor could be that the fighting takes the mammals away from known Ukrainian waters and into unfamiliar foraging areas, where they may be more likely to end up entangled or stranded on land.

The situation is also exacerbated by the fact that experts have identified coastal areas near Ukraine as vital for certain populations of dolphins and porpoises. Hoyt co-chairs the International Union for Conservation of Nature’s Marine Mammal Protected Areas Working Group, which seeks to identify areas of importance to marine mammal conservation.

Several locations around Ukraine – including some that have been affected by fighting – have previously been designated as important habitats, including areas around the Crimean Peninsula, the Kerch Strait and the Sea of ​​Azov, as shown in this interactive map.

The areas were identified as important habitats for three species classified by the IUCN as threatened or endangered: the Black Sea common dolphin, the Black Sea harbor porpoise and the Black Sea bottlenose dolphin.

“Of course, there are fears that dolphins and porpoises that are known to use these areas year-round will have been killed or driven away,” Hoyt said. “But since no research can be done there now, we simply won’t know until after the war is over.”

This article was originally published by Business Insider.

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